#include<stdio.h>
#define MMAX 100000

int main()
{
struct st{int x,y;};
st v[MMAX+1];
int n,m,k,sol,i,x,y,aux=0;
freopen("stergeri.in","r",stdin);
freopen("stergeri.out","w",stdout);
scanf("%d%d%d",&n,&m,&k);
for(i=0;i<m;i++) scanf("%d%d",&v[i].x,&v[i].y);
sol=k;
for(i=m-1;i>=0;--i)
	if(sol>=v[i].x) sol+=v[i].y-v[i].x+1;
printf("%d",sol);
return 0;
}